This invention relates to a process for producing a shaped article having superior resistance to corrosion, heat and oxidation.
The present inventors previously developed a method for producing a corrosion-, heat- and oxidation-resistant material, which comprises coating the surface of a ceramic powder with a semi-inorganic compound such as a polycarbosilane or polycarbosiloxane, molding the coated powder into the desired shape by a suitable molding method such as mold pressing or extrusion, and heat-treating the molded article. They disclosed this method in U.S. Pat. No. 4,117,057, U.S. Pat. No. 4,110,386, U.S. Pat. No. 4,122,139, and U.S. Pat. Application Ser. No. 5,882 filed Jan. 23, 1979.
The present invention provides a simpler and more economical process for producing a corrosion-, heat- and oxidation-resistant shaped article than the prior art mentioned above. The process of this invention comprises coating not a powder but a shaped article with a semi-inorganic compound, and then heat-treating the coated article. Thus, the step of molding a powder which is essential to the prior art method can be omitted.